The secrets behind Renault's V8 engine
The RS26 is a pure expression of Renault technology. Inspired by the solutions that brought world championship success with the RS25 V10 last year, the engineers have exploited the opportunity offered by regulation change, to push the limits of the rules in producing a front-running Formula 1 engine. After completing thousands of miles on the dyno, the V8 impressed with its reliability as soon as it hit the track. In its first three tests, the engine has completed over 5000 km – an increase of more than 15% relative to 2005 at the same stage. Its designers sat down to explain some of the key points of this new engine.
The RS26 Programme:
Léon Taillieu, Project Manager: “Engine design is all about organisation and planning. In modern F1, that is what can make the difference. We rely heavily on our computer tools, which allow us to limit the risk of error. We also conducted specific testing on the V10, which was of significant benefit to the programme.”
Rob White, Technical Director: “The regulations now impose several limits on the engine builders: as well as the V8 architecture and 2.4L capacity, specified limits for the location of the centre of gravity, a maximum bore, and the use of specific materials for certain components. Variable inlet trumpets are no longer legal either. However, the V8 design has not brought about a revolution in the technology we use: the RS26 and RS25 engines have the same DNA.”
Vibrations:
Léon Taillieu: “For every engine, one must draw a distinction between internal and external vibrations. The first category are primarily the torsional vibrations, that are caused by the engine’s moving parts. Understanding these vibrations is crucial to the engine’s basic reliability, and they depend on, among other factors, the firing order of the engine – which is itself a major performance factor. We therefore must choose the firing order that gives us the best reliability-performance compromise.
“The second order of vibrations, concerns those of the static parts of the engine, that are transmitted to components around the engine, and these can be minimised by the way in which the crankshaft is balanced. In the car, the driver and chassis components notice this second order of vibration. The compromise we have selected with our V8 does not bring a superior level of vibration to those we experienced with the V10.”
Performance:
Léon Taillieu: “The average revs over a lap will be around 400 to 500 rpm higher than with the V10. That is a significant difference. Furthermore, because there will be less power than in 2005, the time spent at full throttle will also be higher. We will have to take this into account when deciding how to use the engine over a race weekend.”
Rob White: “The power loss relative to 2005 is around 20% - in line with the reduction in capacity. The torque levels are also lower, because we can no longer use variable inlet trumpets. There is now a more pronounced performance ‘peak’ in the rev range, either side of which the loss of power is quite significant. To be quick, we need to stay on this peak as much as possible. In terms of engine speed, I expect maximum revs at the start of the season will be similar to those seen with the V10, and will climb progressively through the year.”
The consequences at the track:
Denis Chevrier, Trackside Operations Manager: “In terms of our trackside operations, the main changes are down to the new qualifying format, and the possibility to change tyres during the race. With our colleagues in Enstone, we have built new programmes for how we will run during the race weekends: how should we tackled the three-part qualifying session? When should we do our tyre evaluations? The regulations change how we use the car, and we have tried to respond to this in the best way possible.”
Reliability:
Léon Taillieu: “Reliability is our foremost priority. It was a strength of ours in 2005, and must remain so in 2006. We have put all the necessary systems in place, to achieve our objectives in this area.”
Rob White: “As always, we are aiming for zero defect reliability. We have been given a new challenge, and our job is to meet is as best we can. In general, the V8 will run at higher revs. This could pose problems for the reliability, but it has been taken account since the engine’s initial design. So, there are no specific problems for reliability: the RS26 has been designed to be used in a different way to the V10.”
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